Claims:We Claim:

1. Alkyl ketene dimer hydrophobized acrylic emulsion comprising a reaction product of alkyl ketene dimer (AKD) and modified latex including functionality for hydrophobization in the presence of alkyl ketene dimer (AKD) as a hydrophobized emulsion.

2. Alkyl ketene dimer hydrophobized acrylic emulsion as claimed in claim 1 wherein said modified latex comprise at least one hydroxy functional monomer modified latex and said alkyl ketene dimer comprise a dispersion of alkyl ketene dimer (AKD) including alkyl ketene dimer based reactive wax additive.

3. Alkyl ketene dimer hydrophobized acrylic emulsion as claimed in anyone of claims 1 or 2 comprising hydrophobic films/ coats for surface coating wherein said hydrophobized films/ coats are clear or pigmented having water contact angle in the range of 80-110? based on reaction temperature and drying temperature of said film/ coat.

4. Alkyl ketene dimer hydrophobized acrylic emulsion as claimed in anyone of preceding claims 2 to 3 wherein said hydroxy functional monomer modified latex is selected from acrylic, styrene/acrylic latex.

5. Alkyl ketene dimer hydrophobized acrylic emulsion as claimed in anyone of claims 1 to 4 comprising hydroxyl functional monomer selected from anyone or more hydroxyl ethyl methacrylate (HEMA), hydroxy propyl (meth)acrylate, hydroxy butyl (meth)acrylate, hydroxydecyl (meth)acrylates, caprolactone (meth)acrylates, 2-ethyl-3-hydroxyhexyl methacrylate, 1-propyl-2-ethyl-3 hydroxypropyl methacrylate, 1-ethyl-2-methyl-3-hydroxypropyl methacrylate, 2-methyl-3-hydroxypentyl methacrylate, 2,2,4-trimethyl-3-hydroxypentyl methacrylate, 2-propyl-3-hydroxyheptyl methacrylate, 1-butyl-2-propyl-3-hydroxypropyl methacrylate, 2-ethyl-3-hydroxyheptyl methacrylate, 1-butyl-2-ethyl-3-hydroxypropyl methacrylate, 2-propyl-3-hydroxypropyl methacrylate, 2-ethyl-3-hydroxypropyl methacrylate, 1-i-butyl-2-i-propyl-3-hydroxypropyl methacrylate, 2-i-propyl-3-hydroxy-5-methylhexyl methacrylate, 1-methyl-2-i-propyl-3-hydroxypropyl methacrylate, 2-i-propyl-3-methyl-3-hydroxypropyl acrylate, 1-i-butyl-3-hydroxypropyl methacrylate, 3-hydroxy-5-methylhexyl methacrylate, 1-methyl-2-butyl-3-hydroxypropyl methacrylate, 2-butyl-3-hydroxybutyl methacrylate, 1-i-propyl-2,2-dimethyl-3-hydroxypropyl methacrylate,and 2,2-dimethyl-3-hydroxy-4-methylpentyl methacrylate, (HEMA-10) Poly Ethoxy (10) ethyl methacrylate, Hydroxypolyethoxy (10) Allyl Ether, TrimethylolpropaneMonoallyl Ether.

6. Alkyl ketene dimer hydrophobized acrylic emulsion as claimed in anyone of preceding claims 1-5 wherein said alkyl ketene dimer (AKD) comprises anyone or more octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl, docosyl, tetracosyl, phenyl, benzyl, beta-napthyl, and cyclohexyl ketene dimer dispersion having solids in the range of 5-25 % stabilized by stabilized by water soluble starches including amino groups, quaternary ammonium,cationic groups, cationic polymers having amine and quaternized groups.

7. A one-pot process for the manufacture of alkyl ketene dimer hydrophobized acrylic emulsion as claimed in anyone of preceding claims 1-6 comprising the steps of
(i) providing said modified latex including functionality for hydrophobization in the presence of alkyl ketene dimer (AKD) comprising emulsion polymerizing latex polymer comprising acrylic/styrene-acrylic polymer functionalized with at least one hydroxyl functional monomer;
(ii) reacting alkyl ketene dimer (AKD) including alkyl ketene dimer based reactive wax additive preferably as dispersion after completion of emulsion polymerization in step (i) above to obtain said hydrophobized acrylic emulsion suitable as anyone or more of waterborne binders and films/ coats.

8. A one-pot process as claimed in claim 7 wherein
said step (i) involves emulsion polymerization of said latex polymer with a hydroxyl functional monomer preferably hydroxyl ethyl methacrylate (HEMA);
said step (ii) involves adding 5-10 wt% alkyl ketene dimer (AKD) dispersion (5-25% on solids) dropwise at temperature range of 70-80°C for a period of 20-30 mins in the same pot.

9. A one-pot process as claimed in anyone of preceding claim 7 or 8 wherein said waterborne binders and films/ coats when heated for 10-15 mins at 90-120°C after casting favours instant generation of hydrophobicity achieving contact angle of at least about 105?.

10. A one-pot process as claimed in anyone of preceding claims 7 to 9 wherein said waterborne binders and films/ coats attained thereof when cast and dried for a period of 7-10 days at ambient temperature achieves water contact angle of at least about 92?.

11. A one-pot process as claimed in anyone of preceding claims 7 to 10 wherein said waterborne binders and films/ coats attained with hydroxyl ethyl methacrylate as the hydroxyl functional monomer for functionalization of the acrylic/styrene-acrylic latex and upon reaction with alkyl ketene dimer (AKD) dispersion, achieves a water contact angle of at least 95°on ambient curing of latex films at room temperature and at least 105°for heating at 120°C for 15 mins after 2 hours of applications.

12. A surface treatment /coating composition comprising a reaction product of alkyl ketene dimer (AKD) with modified latex including functionality for hydrophobization in the presence of alkyl ketene dimer (AKD) favoring hydrophobized waterborne binders and films/ coats with water contact angle in the range of 80-110?.

Dated this the 1st day of April, 2016 Anjan Sen
Of Anjan Sen and Associates
(Applicants Agent)
, Description:FIELD OF THE INVENTION

The present invention provides for alkyl ketene dimer hydrophobized acrylic emulsions preferably water borne emulsions and binder/ film/coating compositions comprising the same. A process for the preparation of said hydrophobized water borne acrylic emulsions is also provided to favour coating applications with acceptable hydrophobic properties together with improved microbial and algal resistance together with increased durability.

BACKGROUND ART

Hydrophobization of the waterborne binders for the applications in surface coatings is of enormous interest. Hydrophobization is reported to improve the microbial and algae resistance in the surface coating and increase the durability of the coatings.

The most common methods to improve the hydrophobicity in surface coatings is the usage of fluoro polymers, siloxanes and other long chain hydrophobic monomers like lauryl acrylate, stearyl acrylate etc. Micro and nano-structuring of the surfaces is also utilized to make the surface hydrophobic and behave like lotus leaf surface.

Hydrophobizing reagents for imparting water repellency characteristics in textiles, carpets, paper, paperboards etc. are widely known in literature. Some of these reagents include organo complexes, waxes, wax-metal emulsions, silicone, rosins, alkylketene dimers and fluoro chemicals [M. Hayek in the Encyclopedia of Chemical Technology, Volume 24, (1984), “Waterproofing and Water/Oil Repellency”, 442-465]. Paraffin wax emulsions are also effective to improve moisture resistance in paper but are not durable in long run [Youngquist JA Wood-based composites and panel products.General technical report FPL; GTR-113, Service UF, Forest Products Laboratory, (1999) 10.11–10.31]
Alkyl Ketene Dimer (AKD) and ASA alkenyl succinic anhydride both are internal paper sizing reagent which can esterify with the cellulosic components in wood and result in surface modification. The process improves the paper properties like wet strength, printability and resistance against fluid penetrationas disclosed in US4820582.
For general applications in paper industry, the AKD dispersions are stabilized by cationic starch which helps the anchoring of the dispersion to the negatively charged fibre surface.
Alternates to cationic charged starch are available like anionic starch, amphoteric starch, water soluble cellulose ethers, polyacrylamides, polyvinyl alcohol, and polyvinylpyrrolidoneglyoxalatedpolydadmac as directed in US20140336314A1.
The AKD emulsion may have the general formula [RCH=C=O], wherein R is an alkyl group, saturated or unsaturated having from 6 to 22 carbon atoms, cycloalkyl group, aryl, aralkyl or alkaryl group. These known AKD's are as described in US 2,785,067.

The AKD may be a single component or may be also a mixture of many AKD variants. AKD's include decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl, docosyl, tetracosylcyclohexyl, phenyl and benzyl beta napthyl ketene dimers and also AKD's prepared from palmitoleic acid, oleic acid, ricinoleic acid, linoleic acid, linolenic acid, myristoleic acid and eleostearic acid or mixtures thereof.
The two competing chemical reactions during the treatment of cellulose with the AKD emulsion is the esterification to form ß-keto ester and reaction with water to form ß-keto acid which upon decarboxylation generates ketone. Alkyl ketene dimers upon solidification from its melt forms fractal surface pattern. The development of fractal pattern is both time and temperature dependant. Above the melting point, the fractal surface develops at a faster rate. Non–fractal surfaces have water contact angles of 109°. Fractal surfaces are highly rough and generate water contact angles upto 174°. [L. Yan, K. Wang and L. Ye, J. Mater. Sci. Lett., 2003, 22, 1713. 51. S. Shibuichi, T. Onda, N. Satoh and K. Tsujii, J. Phys. Chem., 1996, 100, 19512. 52. R. Mohammadi, J. Wassink and A. Amirfazli, Langmuir, 2004, 20, 9657]
Hydrophobization of materials by using AKD emulsions have been majorly applied in the field of paper sizing industry whereby AKD emulsions are used as sizing agents. The surfaces described are cellulosic materials and wood derivatives. The final applications are from development of moisture proof coatings, photographic coatings, wood and cellulosic fibers. The applications may be summarized as development of water resistant capability in paper.
Patent US2281589 is granted to Dupont as early as in 1942 for using AKD dispersions for making moistureproof wrapping material for packaging of foodstuff.
US2762270 describes usage of AKD dispersions for papersizing as a replacement of wax, rosin and asphaltic material to generate a chemically bound agent on the cellulosic fibers is granted to Hercules Powder Co Ltd in 1956.
US2835578 is granted to Eastman Kodak Co for producing waterproof and chemical resistant photographic paper by using alkyl ketene dimers in 1958.
Patent US3029163 is granted to Dow chemical Co in 1962 for treatment of wood by AKD for improving its adhesion to the non-polar materials.
Some of the patents also describe hydrophobization of inorganic particles like titanium dioxide, colloidal silica, alumina and zirconia to achieve better opacity and retention in the paper during manufacturing. Again, the inorganic particles are not subjected for usage in coatings. PCT International Application WO/1992/018695describes the usage of AKD dispersions for improved retention on the cellulosic fibers in paper for better opacity. In this case, the grinding of titanium dioxide is carried out in acidic medium in presence of cationically charged AKD emulsions.

On similar lines, US5433776 granted to Hercules Incor. (18Jul 1995) is related to sizing of paper by AKD modified colloidal silica, alumina and zirconia.

Fluorinated alkyl ketene dimers are used as sizing materials for cellulosic materials on similar lines. Usage of fluorinated aldoktene dimer for oil and water resistant sizing for cellulosic materials is described in European Patent Application EP0543363 where perfluoro groups are a part of AKD.

Hydrohobization of cellulose based materials for producing hydrophobic dispersing agents and usage in paints is also described. However, the method is limited to cellulosic materials. US6600033 granted to Metsa Specialty Chemicals Oy in 2003 describes hydrophobization of cellulose ether by AKD’s which can be used as dispersing agents in detergents, paper coating mixtures, paints, oil drilling muds.

Alkyl ketene dimers also known to hydrophobize textiles like wool and synthetic fibres like polyamides fibres as described in US5028236 granted to Bayer Aktiengesellschaft in Jul 1991.The process does not cover any coatings compositions.

US20140130710A1 discloses usage of alkyl ketene dimer dispersions to hydrophobize nanocellulose particles which can be subsequently used to make superhydrophobic surfaces by chemical vapor deposition or spray drying.

While it is apparent from the above discussions that there is no available state of the art knowledge on the use of alkyl ketene dimer for polymeric modifications of latex and coating materials thereof, there is a longfelt need in the art to explore hydrophobization of coating compositions by employing said alkyl ketene dimer emulsions and a method of producing a hydrophobic surfacewith acceptable hydrophobic properties that would also have improved microbial and algal resistance together with increased durability.

OBJECTS OF THE INVENTION

It is thus the primary object of the present invention to provide for hydrophobized acrylic emulsions preferably waterborne acrylic emulsions involving Alkyl Ketene Dimer (AKD) dispersion and a process of preparing the same to facilitate waterborne binders andlatex films/coats thereof that has acceptable hydrophobic properties and is permanently hydrophobic with contact angle of at least 80°.

It is another object of the present invention to provide for said waterborne binders that are permanently hydrophobized to also improve the microbial, algae resistance and durability of the surface coating involving the same.

It is yet another object of the present invention to provide for a process of manufacture of said hydrophobized acrylic emulsions preferably waterborne involving Alkyl Ketene Dimer (AKD) dispersion that would be made to react with the latex system in a facile manner enabling processible dispersion and coating formulations/applications involving the same.

SUMMARY OF THE INVENTION

Thus according to the basic aspect of the present invention there is provided alkyl ketene dimer hydrophobized acrylic emulsion comprising a reaction product of alkyl ketene dimer (AKD) and modified latex including functionality for hydrophobization in the presence of alkyl ketene dimer (AKD) as a hydrophobized emulsion.

Preferably in said alkyl ketene dimer hydrophobized acrylic emulsion said modified latex comprise at least one hydroxy functional monomer modified latex and said alkyl ketene dimer comprise a dispersion of alkyl ketene dimer (AKD) including alkyl ketene dimer based reactive wax additive.

It is thus a surprising finding by way of the present invention that hydrophobization of binders preferably waterborne acrylic emulsion for surface coating application is made possible based on the attainment of alkyl ketene dimer hydrophobized acrylic emulsion which is a reaction product of alkyl ketene dimer (AKD) and modified latex including functionality for hydrophobization in the presence of alkyl ketene dimer (AKD).

It was found that only when the latex was modified with a particular functionality the same enabled hydrophobization of the latex in the presence of alkyl ketene dimer (AKD) including alkyl ketene dimer based reactive wax additives. Significantly thus it was found that only when said latex was modified with at least one hydroxy functional monomer preferably hydroxyl ethyl methacrylate (HEMA) the same reacted with alkyl ketene dimer (AKD) including alkyl ketene dimer based reactive wax additive to yield alkyl ketene dimer hydrophobized acrylic emulsion.

Advantageously, said hydrophobization also improved the microbial and algae resistance of the surface coats/films that increased the durability of the coatings.

According to a preferred aspect of the present invention the alkyl ketene dimer hydrophobized acrylic emulsion comprise hydrophobic films/ coats for surface coating wherein said hydrophobized films/ coats are clear or pigmented having water contact angle in the range of 80-110? based on reaction temperature and drying temperature of said film/ coat.

According to yet another preferred aspect of the present invention the alkyl ketene dimer hydrophobized acrylic emulsion is provided wherein said hydroxy functional monomer modified latex is selected from acrylic, styrene/acrylic latex.

Preferably said alkyl ketene dimer hydrophobized acrylic emulsion comprises hydroxy functional monomer selected from anyone or more hydroxyl ethyl methacrylate (HEMA), hydroxy propyl (meth)acrylate, hydroxy butyl (meth)acrylate, hydroxydecyl (meth)acrylates, caprolactone (meth)acrylates, 2-ethyl-3-hydroxyhexyl methacrylate, 1-propyl-2-ethyl-3 hydroxypropyl methacrylate, 1-ethyl-2-methyl-3-hydroxypropyl methacrylate, 2-methyl-3-hydroxypentyl methacrylate, 2,2,4-trimethyl-3-hydroxypentyl methacrylate, 2-propyl-3-hydroxyheptyl methacrylate, 1-butyl-2-propyl-3-hydroxypropyl methacrylate, 2-ethyl-3-hydroxyheptyl methacrylate, 1-butyl-2-ethyl-3-hydroxypropyl methacrylate, 2-propyl-3-hydroxypropyl methacrylate, 2-ethyl-3-hydroxypropyl methacrylate, 1-i-butyl-2-i-propyl-3-hydroxypropyl methacrylate, 2-i-propyl-3-hydroxy-5-methylhexyl methacrylate, 1-methyl-2-i-propyl-3-hydroxypropyl methacrylate, 2-i-propyl-3-methyl-3-hydroxypropyl acrylate, 1-i-butyl-3-hydroxypropyl methacrylate, 3-hydroxy-5-methylhexyl methacrylate, 1-methyl-2-butyl-3-hydroxypropyl methacrylate, 2-butyl-3-hydroxybutyl methacrylate, 1-i-propyl-2,2-dimethyl-3-hydroxypropyl methacrylate,and 2,2-dimethyl-3-hydroxy-4-methylpentyl methacrylate, (HEMA-10) Poly Ethoxy (10) ethyl methacrylate, Hydroxypolyethoxy (10) Allyl Ether, TrimethylolpropaneMonoallyl Ether.

More preferably said alkyl ketene dimer hydrophobized acrylic emulsion is provided wherein said alkyl ketene dimer (AKD) comprises anyone or more octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl, docosyl, tetracosyl, phenyl, benzyl, beta-napthyl, and cyclohexyl ketene dimer dispersions having solids in the range of 5-25 % stabilized by water soluble starches including amino groups, quaternary ammonium,cationic groups, cationic polymers having amine and quaternized groups.

According to another aspect of the present invention there is provided a one-pot process for the manufacture of alkyl ketene dimer hydrophobized acrylic emulsion comprising the steps of

(i) providing said modified latex including functionality for hydrophobization in the presence of alkyl ketene dimer (AKD) comprising emulsion polymerizing latex polymer comprising acrylic/styrene-acrylic polymer functionalized with at least one hydroxyl functional monomer;

(ii) reacting alkyl ketene dimer (AKD) including alkyl ketene dimer based reactive wax additive preferably as dispersion after completion of emulsion polymerization in step (i) above to obtain said hydrophobized acrylic emulsion suitable as anyone or more of waterborne binders and films/ coats.

Preferably in said one-pot process
said step (i) involves emulsion polymerization of said latex polymer with ahydroxyl functional monomer preferably hydroxyl ethyl methacrylate (HEMA);

said step (ii) involves adding 5-10 wt% alkyl ketene dimer (AKD) dispersion (5-25% on solids) dropwise at temperature range of 70-80°C for a period of 20-30 mins in the same pot.

Preferably said one-pot process is provided wherein said waterborne binders and films/ coats attained when heated for 10-15 mins at 90-120°C after casting favours instant generation of hydrophobicity achieving contact angle of at least about 105?.

Thus addition of AKD was carried out at the post polymerization (temp 70-80 degree C) stage. For measuring the hydrophobicity of the latex a film was cast from the prepared latex. When a film is cast the hydrophobicity (contact angle) is achieved after 7-10 days of drying the film at ambient temperatures. However, if the film is heated at 90-120 ?C for 10-15 mins after casting the hydrophobicity is developed immediately. In case of paint (made out of the said latex) same trend is observed. Thus the instant hydrophobicity is attained after film formation on glass plate and its subsequent heating.

Advantageously therefore in said one-pot process wherein said waterborne binders and films/ coats attained thereof when cast and dried for a period of 7-10 days at ambient temperature achieves water contact angle of at least about 92?.

More advantageously, a one-pot process is provided wherein said waterborne binders and films/ coats attained with hydroxyl ethyl methacrylate as the hydroxyl functional monomer for functionalization of the acrylic/styrene-acrylic latex and upon reaction with alkyl ketene dimer (AKD) dispersion, achieves a water contact angle of at least 95°on ambient curing of latex films at room temperature and at least 105°for heating at 120°C for 15 mins after 2 hours of applications.

According to another aspect of the present invention there is provided a surface treatment /coating composition comprising a reaction product of alkyl ketene dimer (AKD) with modified latex including functionality for hydrophobization in the presence of alkyl ketene dimer (AKD) favoring hydrophobized waterborne binders and films/ coats with water contact angle in the range of 80-110?.

The present invention is described hereunder in greater details in relation to the non-limiting exemplary illustrations.

DETAILED DESCRIPTION OF THE INVENTION

As discussed hereinbefore the present invention provides for alkyl ketene dimer hydrophobizedacrylic emulsion preferably waterborne emulsions and binders, film/coating compositions comprising the same. A process for the preparation of said alkyl ketene dimer hydrophobized acrylic emulsion hydrophobized water borne acrylic emulsions is also provided to favour surface coating applications with acceptable hydrophobic properties that also possesses improved microbial and algal resistance together with increased durability.

It is thus a significant finding of the present invention to provide for hydrophobized latex/acrylic emulsions preferably water borne by using AKD (alkyl ketene dimer) dispersion which latex when only modified with hydroxyl functional monomer preferably hydroxyl ethyl methacrylate (HEMA) results in a reaction product of said hydroxyl functional monomer modified latex and AKD dispersion,as permanently hydrophobized water borne acrylic emulsions, suitable for coating applications providing contact angle of at least 80°and improved microbial, algae resistance and durability involving the same.

It was thus surprisingly found by way of the present invention that only upon modifying the latex (acrylic, styrene/ acrylic) with hydroxy functional monomer preferably hydroxyl ethyl methacrylate (HEMA) the same could be reacted with AKD (alkyl ketene dimer) dispersion under facile reaction conditions for necessary hydrophobization of the latex and to provide for a reaction product as hydrophobized water borne acrylic emulsions of the same for said coating applications.

Importantly, it was found that in the absence of any hydroxyl functional monomer modification of the latex (acrylic, styrene/ acrylic), the AKD (alkyl ketene dimer) dispersion fails to react with the latex and the processability of the thus attained latex emulsion in the absence of such hydroxy functional monomer modification is very poor and could not be used for further applications. Thereby the hydrophobicity of such systems were not measurable/applicable.

The alkyl ketene dimers of the present invention includes octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl, docosyl, tetracosyl, phenyl, benzyl, beta-napthyl, and cyclohexyl ketene dimers.

Such AKD dispersions of the present invention are either stabilized by water soluble starches containing amino groups, quaternary ammonium or other cationic groups OR cationic polymers having amine and quaternized groups.

Hydroxy functionality based monomers for the modification of said latex is preferably hydroxyl ethyl methacrylate (HEMA) and includes anyone or more of following monomers:
Hydroxy ethyl (meth)acrylate, hydroxy propyl (meth)acrylate, hydroxy butyl (meth)acrylate, hydroxydecyl (meth)acrylates, caprolactone (meth)acrylates, 2-ethyl-3-hydroxyhexyl methacrylate, 1-propyl-2-ethyl-3 hydroxypropyl methacrylate, 1-ethyl-2-methyl-3-hydroxypropyl methacrylate, 2-methyl-3-hydroxypentyl methacrylate, 2,2,4-trimethyl-3-hydroxypentyl methacrylate, 2-propyl-3-hydroxyheptyl methacrylate, 1-butyl-2-propyl-3-hydroxypropyl methacrylate, 2-ethyl-3-hydroxyheptyl methacrylate, 1-butyl-2-ethyl-3-hydroxypropyl methacrylate, 2-propyl-3-hydroxypropyl methacrylate, 2-ethyl-3-hydroxypropyl methacrylate, 1-i-butyl-2-i-propyl-3-hydroxypropyl methacrylate, 2-i-propyl-3-hydroxy-5-methylhexyl methacrylate, 1-methyl-2-i-propyl-3-hydroxypropyl methacrylate, 2-i-propyl-3-methyl-3-hydroxypropyl acrylate, 1-i-butyl-3-hydroxypropyl methacrylate, 3-hydroxy-5-methylhexyl methacrylate, 1-methyl-2-butyl-3-hydroxypropyl methacrylate, 2-butyl-3-hydroxybutyl methacrylate, 1-i-propyl-2,2-dimethyl-3-hydroxypropyl methacrylate,and 2,2-dimethyl-3-hydroxy-4-methylpentyl methacrylate, (HEMA-10) Poly Ethoxy (10) ethyl methacrylate, Hydroxypolyethoxy (10) Allyl Ether, TrimethylolpropaneMonoallyl Ether could also be the monomers which can impart the desired property in the latex.

Example 1: Process of preparing hydrophobized water borne acrylic emulsions involving alkyl ketene dimer dispersions.
According to a process embodiment, the AKD dispersion stabilized by cationic starch is added while emulsion polymerization of acrylic/styrene-acrylic polymer functionalized with hydroxyl functional monomer such as hydroxyl ethyl methacrylate (HEMA). AKD dispersion is added in the temperature range of 70-80°C after emulsion polymerization is complete. The addition of AKD dispersion was carried out drop wise directly in the reactor for a period of 20-30 mins to yield a polymerization product involving said AKD as hydrophobized water borne acrylic emulsions. The hydrophobic property of the latex dispersion was achieved by addition of 5-10% of AKD dispersion (10% solids) to yield the hydrophobic polymerized latex. Usage of concentrations more than the quantity saturates the hydrophobic property.
It was found that a large quantity of coagulum is obtained in the absence of any hydroxy functionalization of the latex (acrylic, styrene/ acrylic) polymer when AKD dispersion was added to it.
Also simple blending of AKD dispersion and hydroxyl functionalized latex at ambient temperature doesn’t yield said hydrophobic property of the latex which is only attained when the reaction at the desired temperature range is carried out. The reaction at said temperature range of 70-80°C is required to achieve the desired hydrophobic property.
Hence the acrylic /styrene-acrylic latexes only when modified by hydroxy functional monomer reacts with cationic starch stabilized AKD when reacted at a temperature range 70-80°C to provide for hydrophobized water borne acrylic emulsions with acceptable hydrophobic property.

The acceptable range of hydrophobicity is the one where water contact angle of the dried latex /paint films is more than 80°. The most preferred hydrophobic property is obtained with hydroxyl ethyl methacrylate as the monomer for functionalization for the acrylic/styrene-acrylic latex. The water contact angle for the same is at least 95° on ambient curing of latex films at room temperature and at least 105°for heating at 120°C for 1 mins after 2 hours of applications.

According to said process of the present invention while the same provides for a one-pot synthesis of hydrophobized water borne acrylic emulsions suitable for coating applications comprising polymerization product of AKD dispersions with acrylic and styrene/acrylic modified latex, modified with hydroxy functionalized monomers such as (HEMA),the same involves some critically essential process parameters viz.:
sequence of addition of the AKD dispersion that is added after emulsion polymerization of acrylic/styrene-acrylic polymer functionalized with hydroxyl ethyl methacrylate; the temperature of addition of AKD dispersion which is added in the temperature range of 70-80°C after emulsion polymerization is complete; drop wise addition of AKD dispersion directly in the reactor for a period of 20-30 mins to facilitate a one-pot process;
addition of 5-10 wt.% of AKD dispersion (5-25% on solids) to achieve the desired hydrophobic property of the waterborne binders and films/ coats attained thereof wherein usage of concentrations more than the quantity saturates the property;
said waterborne binders and films/ coats when heated for 10-15 mins at 90-120°C after casting favours instant generation of hydrophobicity achieving contact angle of at least about 105? which otherwise at ambient temperature takes 7-10 days to develop to achieve water contact angle of at least about 92?.

Therefore the AKD reacts with hydroxy functionalized preferably HEMA functionalized (acrylic /styrene-acrylic) latexwhereby hydrophobicity of the latex is attained due to this reaction and a hydrophobized water borne acrylic emulsions suitable for coating applications could bethus achieved. Hydrophobicity was measured for the latex film. Once the latex is prepared, if films (latex without pigments) are prepared and kept at room temperature hydrophobicity starts developing.Water contact angle attained after 7-10 days of ambient drying 92° [for latex film]
However, if the films are prepared and heated at 90-120?C, hydrophobicity develops quickly and a contact angle of 107 degree is obtained after 15 minutes of drying. Thus it was found by way of the present invention that heating accelerates the reaction thereby achieving hydrophobicity quickly. In case of paint films (latex with pigments) similar observations are noticed.
Examples 2: An exemplary recipe based on the above process is illustrated below:

Demineralized water–22-25% water; Non-ionic surfactant (alcohol ethoxylates with 19-20 mole ethoxylation)-0.05-0.2 wt%; Polymerizable anionic reactive surfactant -0.15-0.25 wt%; Potassium per sulphate -0.025-0.2 wt%; Sodium bi carbonate- 0.01-0.2 wt% is taken in reactor A
Pre-emulsion (B) is formed by taking Demineralized water-13-17 wt%; Polymerizable anionic reactive surfactant -0.8-1.2 wt%; Non-ionic surfactant (alcohol ethoxylates with 19-20 mole ethoxylation)-0.1-0.25 wt%; Methyl methacrylate- 22-25 wt%; 2-ethyl hexyl acrylate- 18-20 wt%; Glacial Methacrylic acid-0.6-0.9 wt%;
After 45 mins of PE addition, Adhesion promoter I-0.1-0.25 wt% is added and after 2hrs addition in PE, Hydroxy ethyl methacrylate- 0.75-1.25% is added and flushed with water- 0.25-1%;
Digestion (C) comprises addition of Tertiary butyl hydroperoxide -0.02-0.05 wt%; Sodium formaldehyde sulphoxylate-0.03-0.05 wt%; Polymerizable anionic reactive surfactant -0.1-0.25 wt%
After completion of digestion, addition of AKD dispersion followed, AKD dispersion (15-20% solids): 5 - 10%, Flush water: 1 - 2.5% followed by the addition of Additives of Biocide -0.2 wt%, Neutraliser-0.6-0.9 wt% (to adjust pH 7), Water – Balance to get 50% solid.
The contact angle (O, theta) is defined as the angle formed by the intersection of the liquid-solid interface and the liquid-vapor interface. Contact angle (O, theta) and surface energy is obtained by Digidrop from GBX instrument by sessile drop method. Films of 150µ thickness were casted and dried. A droplet size of ~ 5 µL is dropped on the glass plate by a syringe containing water. After putting the drop on the film, 10 second equilibration time is given so that the droplet gets time to spread. After that, Water Contact Angle is measured by theta/2 method.
It is thus possible by way of the present invention to provide for alkyl ketene dimer hydrophobized acrylic emulsion preferably waterborne emulsions and binders, film/coating compositions comprising the same. A process for the preparation of said alkyl ketene dimer hydrophobized acrylic emulsion preferably hydrophobized water borne acrylic emulsions is also provided to favour surface coating applications with acceptable hydrophobic properties that also possesses improved microbial and algal resistance together with increased durability.